I’m just trying to figure out how the GS500F is perfect for you but the Ninja 250r does not fit your style? To my eye the styling of the GS500F fits right in between the older Ninja 250 and the newer one. However all 3 have sport bike styling with standard riding positions.
The older Ninja 250 especially has good value on the used market. Most are under $2000. You should not have too much trouble finding a GS500F for near $2000 and a used Ninja 500r can also be in this price range.
A TU250x is a nice small standard with a retro look. And you should be able to find some dual sports below $3000.